Download Hyponatraemia prior to discharge from hospital after a general

1743
Hyponatraemia prior to discharge from hospital after a general medical admission is
associated with a significantly increased risk of readmission within 28 days.
Solanki, P; Whitelaw, B; Miell, J; Alywin, S
Endocrine Department, King’s College Hospital
Background: Hyponatraemia is associated with adverse outcomes including increased
mortality and risk of falls. It is not previously known whether hyponatraemia, on discharge
from hospital, is associated with an increased risk of readmission.
Method: We conducted a retrospective cohort study identifying all patients admitted to a UK
teaching hospital as emergency general medical admissions over a two month period. We
identified all readmissions within 28 days of discharge and collected data on diagnosis, drug
treatment, admission, nadir and discharge serum sodium. Hyponatraemia was defined as [Na]
< 135 mmol/L). Patients who died during the initial admission or who remained in hospital
were excluded from the study.
Results: 1527 patients were included in the dataset. 26% (397/1527) of patients demonstrated
hyponatraemia at some point during their admission and 9% (141/1527) were hyponatraemic
at discharge. 238 (16%) patients were readmitted within 28 days. Hyponatraemia at discharge
(Na 135 mmol/l) was associated with an increased risk of re-admission, odds ratio 1.7
(p=0.0155). Moderate or severe hyponatraemia (Na<130 mmol/l) showed a stronger
association with readmission: odds ratio 3.4 (p=0.007). The prevalence of congestive cardiac
failure and the use of anticonvulsant medication were both significantly higher in the readmitted group (16% vs 6% and 22% vs11% respectively).
Conclusion: This study identified hyponatraemia on discharge from hospital as a significant
and potentially avoidable risk factor for readmission within 28 days.